This application relates to medical x-ray positioners and in particular to a positioner using independently articulated arms to support the x-ray source and x-ray detector.
Conventional x-ray positioners provide mechanical supports to hold an x-ray source and x-ray detector in opposition about a patient for a limited number of specific procedures. For procedures in which the patient is standing, the x-ray source may be attached to a pillar allowing adjustment in its height as directed toward an x-ray detector attached to an opposing wall or a second similar pillar. For procedures in which the patient is supine, the x-ray source and detector may be attached to opposite sides of a patient table. Alternatively the x-ray source and the detector may be attached to opposite ends of a C-arm which is supported by a sliding collar allowing the angle of the x-rays through the patient to be varied.
Multi-axis robotic arms, positioned above and below the patient table, have been proposed to provide support for the x-ray source and x-ray detector such as may reduce interference between the support structure and other equipment and personnel. See, for example, U.S. Pat. No. 6,200,024 to Negrelli citing U.S. Pat. No. 4,894,855 to Kresse.
Such systems require complex multi-axis movement for simple adjustments of the x-ray tube and detector in angulation or translation, and appear to have limited utility for certain common x-ray procedures such as those requiring the patient to stand. Further such systems make it difficult or impossible to swap the location of the x-ray source from beneath the patient to above the patient, when the patient is supine, and an improved image might thereby be obtained.
Moreover, conventional systems have a fixed number of axes of freedom, thus producing a positioner that may be unsuitable for a desired application that requires complex translation and rotation of the source and detector. In other applications, the positioner may provide more axes of freedom than desired, which increases cost to the end user who has no choice but to purchase a positioner that is more complex than necessary for the intended end use.
The present invention provides a modular mechanism for independently supporting an x-ray tube and detector with varying degrees of positioning flexibility depending on the end user application. Generally the invention provides an x-ray source producing an x-ray beam and an x-ray detector detecting x-rays received from the x-ray source. First and second articulated arms are provided, each of which having a distal end supporting the x-ray source and x-ray detector, respectively. Each of the arms includes a plurality of links connected at joints having independent axes of motion. An axis controller sends movement signals to each arm and receives position signals to coordinate movement of the source and detector according to a predefined operating program. The links may be added to and removed from each arm to provide greater or fewer axes of motion for each arm.